APR B5 S4 RSC Exhaust System
Reflective Sound Cancellation allows for maximum Exhaust gas flow while completely eliminating in
cabin sound resonance (drone). RSC™ incorporates innovative technologies
developed in conjunction with NASA. With limited use of packing materials
and no baffles, RSC™ allows for a completely straight and free flowing Exhaust path through the RSC™ mufflers.
Reflective Cancellation bounces the undesirable sound waves into each other
to attenuate the wave and completely eliminate the low frequency tones that
create drone. Each RSC™ muffler is tuned to eliminate specific,
undesirable sound frequencies allowing only the engine's desirable Exhaust notes to be heard and improving
performance.
The B5 S4 in the video has a full APR RSC Exhaust System with an APR Stage III K04 turbocharger System.

500hp Audi S4 test run
Short test drive in a 500hp Audi S4. My friend who owns this car is an
A-TECH and is not exaggerating the horsepower for everyone on
Youtube that thinks they could tell a Car's HP by watching a clip. haha